Active immunotherapy, both specific (neuraminidase-treated tumor cells) and non-specific (BCG) can be used in tumor bearing mice, after chemotherapy, to increase both the median survival time and percent surviving. Mice cured with chemotherapy-immunotherapy protocols develop tumor-specific immunity which can be passively transferred with serum. Proposed studies are designed to evaluate active immunotherapy in mice bearing spontaneous or transplanted breast tumor. Immunotherapy will be used after the primary tumor has been treated with surgery, radiation or chemotherapeutic agents. Cellular and humoral immunity will be evaluated in tumor-bearing mice before, during, and after treatment. Studies are designed to evaluate both afferent and efferent activity using both in vivo and in vitro assays. Properties of membranes and membrane components will be characterized using biochemical, biophysical, and biological parameters. Hopefully, these data will relate host response to the characteristics of cell surface membranes.